<a href="javascript:void(0)" onclick="ajaxSubscribe('<?php echo $author_id ?>')">
    <div class="suscripcion" style="display: block;">
        <div style="display: inline-block;vertical-align: middle;">Suscribirse</div>
        <div style="display: inline-block;vertical-align: middle;"><?php echo image_tag('tick.png','size=16x16') ?></div>
    </div>
</a>